(VINCENNES) - Indiana Conservation Officers along with the Indiana Department of Environmental Management are investigating a fish kill at Four Lakes in Vincennes.

On Thursday June 13 a small amount of copper sulfate was applied to one of the city ponds by a city employee to help control the algae. This is a common practice to help keep ponds clean and maintain an appealing appearance.

As a result of the application approximately 50 -100 fish were later observed dead. According to witnesses fish that were affected included bluegill, crappie and carp.

The small pond measures approximately .75 acres and is located on Wilbur Street in Vincennes.